There is a DC-DC power conversion apparatus in the related art having two or more switching units each of which includes two or more semiconductor switching elements that perform switching operations complementarily. All the semiconductor switching elements of the respective switching units are connected in series. The DC-DC power conversion apparatus also has an energy transition capacitor and an inductor. DC-DC conversion is performed using charging/discharging of the energy transition capacitor by switching operations of the semiconductor switching elements of the respective switching units. Low-voltage withstanding semiconductor switching elements and a small inductor can be used and a ratio of an input voltage and an output voltage can be adjusted by changing ON-duties of the semiconductor switching elements (for example, see Patent Document 1).